The Electric vehicles (EVs) are gaining more and more popularity. An important feature of EVs is the regenerative capabilities enabled with a propulsion motor that also is capable of acting as a generator. This regeneration allows the motion of the vehicle to generate electricity which recharges the battery, thus extending the driving range. Management of this regeneration and calculation of remaining range is a complex issue.
The slope at which the EV is traveling is a significant factor that can be used for various calculations related to the regeneration and range. For example, repeated measurement of slope as an EV travels can help in predicting the number of miles left before the battery is exhausted. It can also aid in controlling the optimal amount of regeneration required. In another example, the slope can be used to advice the driver on driving the EV in a fuel efficient manner or how well they have been driving. Likewise, in an autonomous vehicle, the slope of the road can also be used as a significant factor in computing the desirable EV speed to increase the range.
Presently, the methods used for determining slope of the road or path are costly and complex. The conventional techniques involve use of mechanical devices such as a water tank or pendulum with costly sensor mechanisms, Micro-Electro-Mechanical Systems (MEMS) position or accelerometer sensors. Some of the other methods used for determining the slope of the road involve analysis of transmission gearing, and fuel/air mixture, which are not typically relevant in an EV.